Background (Policies)	9 Months Ended
Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Consolidation policy	To simplify the overall presentation of our consolidated financial statements, we report immaterial amounts attributable to noncontrolling interests in certain of our subsidiaries as follows: (i) income attributable to noncontrolling interests in other income (expense), net, (ii) equity attributable to noncontrolling interests in additional paid-in capital and (iii) cash flows attributable to noncontrolling interests in other, net financing activities.
Reclassification policy	We reclassified certain prior period amounts to conform to the current period presentation, including the categorization of our revenues and our segment reporting. See Note 11—Segment Information for additional information. These changes had no impact on total operating revenues, total operating expenses or net income for any period.
Recently adopted accounting pronouncements and recent accounting pronouncements	Recently Adopted Accounting Pronouncements In the first quarter of 2018, we adopted Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers”, ASU 2018-02, “Income Statement-Reporting Comprehensive Income: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” and ASU 2016-16, “Intra-Entity Transfers of Assets Other Than Inventory”. Each of these is described further below. Revenue Recognition In May 2014, the FASB issued ASU 2014-09 which replaces virtually all existing generally accepted accounting principles on revenue recognition and replaces them with a principles-based approach for determining revenue recognition using a new five step model. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also includes new accounting principles related to the deferral and amortization of contract acquisition and fulfillment costs. We adopted the new revenue recognition standard under the modified retrospective transition method. During the three and nine months ended September 30, 2018, we recorded a cumulative catch-up adjustment that increased our retained earnings by $49 million, net of $17 million of income taxes, and $346 million, net of $117 million of income taxes, respectively. The catch-up adjustment recorded during the three months ended September 30, 2018 resulted from the identification of additional fulfillment costs that should have been considered in our adoption and from correcting certain issues in the accounting system we utilize in calculating revenue under the new revenue recognition standard. Under ASU 2014-09, we are now deferring incremental contract acquisition and fulfillment costs and are recognizing (or amortizing) such costs over either the initial contract (plus anticipated renewal contracts to which the costs relate) or the average customer life. Deferred acquisition and fulfillment costs are amortized based on the transfer of services on a straight-line basis over the average customer life of 30 months for consumer customers and 12 to 60 months for business customers and are included in cost of services and products and selling, general and administrative expenses in our consolidated statement of operations. A portion of these costs are amortized on a portfolio basis using an average expected contract term of 30 months. The amounts of these deferred costs that are anticipated to be amortized in the next twelve months are included in other current assets on our consolidated balance sheets. See Note 5—Revenue Recognition for additional information. Comprehensive Income ASU 2018-02 provides an option to reclassify stranded tax effects within accumulated other comprehensive income to retained earnings in each period in which the effect of the change in the U.S. federal corporate income tax rate in the Act (or portion thereof) is recorded. If an entity elects to reclassify the income tax effects of the Act, the amount of that reclassification shall include the effect of the change in the U.S. federal corporate income tax rate on the gross deferred tax amounts and related valuation allowances, if any, at the date of enactment of the Act related to items remaining in accumulated other comprehensive income. The effect of the change in the U.S. federal corporate income tax rate on gross valuation allowances that were originally charged to income from continuing operations shall not be included. ASU 2018-02 is effective January 1, 2019, but early adoption is permitted and should be applied either in the period of adoption or retrospectively to each period (or periods) in which the effect of the change in the U.S. federal corporate income tax rate in the Act is recognized. We early adopted and applied ASU 2018-02 in the first quarter of 2018. The adoption of ASU 2018-02 resulted in a $407 million increase to retained earnings and in accumulated other comprehensive loss. See Note 14—Accumulated Other Comprehensive Loss for additional information. Income Taxes ASU 2016-16 eliminates the current prohibition on the recognition of the income tax effects on the transfer of assets among our subsidiaries. Prospectively, the income tax effects associated with these asset transfers, except for the transfer of inventory, will be recognized in the period the asset is transferred versus the current deferral and recognition upon either the sale of the asset to a third party or over the remaining useful life of the asset. Our adoption of ASU 2016-16 did not have a material impact to our consolidated financial statements. Recently Issued Accounting Pronouncements Retirement Benefits In August 2018, the FASB issued ASU 2018-14, "Compensation-Retirement Benefits-Defined Benefit Plans-General: Disclosure Framework-Changes to the Disclosure Requirements for Defined Benefit Plans" (“ASU 2018-14“). ASU 2018-14 eliminates requirements for certain disclosures that are not considered cost beneficial, clarifies certain required disclosures and adds additional disclosures under defined benefit pension plans and other postretirement plans. We are required to adopt this guidance beginning January 1, 2021. Early adoption is permitted. The amendments in ASU 2018-14 would need to be applied on a retrospective basis. We are currently evaluating the potential impact of the adoption of this standard on our disclosures. Goodwill Impairment In January 2017, the FASB issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment” (“ASU 2017-04”). ASU 2017-04 simplifies the impairment testing for goodwill by changing the measurement for goodwill impairment. Under current rules, we are required to compute the implied fair value of goodwill to measure the impairment amount if the carrying value of a reporting unit exceeds its fair value. Under ASU 2017-04, the goodwill impairment charge will equal the excess of the reporting unit carrying value above its fair value, limited to the amount of goodwill assigned to the reporting unit. We are required to adopt the provisions of ASU 2017-04 for any goodwill impairment tests, including our required annual test, occurring after January 1, 2020, but have the option to early adopt it for any impairment test that we are required to perform. We have not determined if we will elect to early adopt the provisions of ASU 2017-04. The provisions of ASU 2017-04 would not have affected our last goodwill impairment assessment, but no assurance can be provided that the simplified testing methodology will not affect our goodwill impairment assessment in the future. Financial Instruments In June 2016, the FASB issued ASU 2016-13, "Measurement of Credit Losses on Financial Instruments" ("ASU 2016-13"). The primary impact of ASU 2016-13 for us is a change in the model for the recognition of credit losses related to our financial instruments from an incurred loss model, which recognized credit losses only if it was probable that a loss had been incurred, to an expected loss model, which requires our management team to estimate the total credit losses expected on the portfolio of financial instruments. We are currently reviewing the requirements of the standard and evaluating the impact on our consolidated financial statements. We are required to adopt the provisions of ASU 2016-13 effective January 1, 2020, but could elect to early adopt the provisions as of January 1, 2019. We expect to recognize the impacts of adopting ASU 2016-13 through a cumulative adjustment to retained earnings as of the date of adoption. As of the date of this report, we have not yet determined the date we will adopt ASU 2016-13. Leases In February 2016, the FASB issued ASU 2016-02, “Leases” (“ASU 2016-02”). The core principle of ASU 2016-02 will require lessees to present right-of-use assets and lease liabilities on their balance sheets for operating leases, which under GAAP are currently not required to be reflected on their balance sheets. ASU 2016-02 is effective for annual and interim periods beginning January 1, 2019. Upon adoption of ASU 2016-02, we are required to recognize and measure leases at the beginning of the earliest period presented in our consolidated financial statements using a modified retrospective approach. The modified retrospective transition approach includes a number of optional practical expedients that we may elect to apply. In January 2018, the FASB issued ASU 2018-01, “Leases: Land Easement Practical Expedient for Transition to ASU 2016-02" ("ASU 2018-01"). ASU 2018-01 permits reporting companies to elect to forego reassessments of land easements that exist or expire before the entity’s adoption of ASU 2016-02 and that were not previously accounted for as leases. We plan to adopt ASU 2018-01 at the same time we adopt ASU 2016-02. In July 2018, the FASB issued ASU 2018-11, "Leases: Targeted Improvements" ("ASU 2018-11"). ASU 2018-11 provides entities with an additional (and optional) transition method to adopt the new leases standard. Under this new transition method, an entity initially applies the new leases standard at the adoption date and recognizes a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. We have not yet determined whether we will use ASU 2018-11's newly permitted adoption method. We are in the process of implementing a new lease administration and accounting system. We plan to adopt ASU 2016-02 and ASU 2018-01 effective January 1, 2019. The adoption of ASU 2016-02 will result in our recognition of right of use assets and lease liabilities that we have not previously recorded. Although we believe it is premature as of the date of this report to provide any estimate of the impact of adopting ASU 2016-02, we do expect that it will have a material impact on our consolidated financial statements. Additionally, upon implementing ASU 2016-02, accounting for the failed-sale-leaseback transaction described in Note 3—Sale of Data Centers and Colocation Business will no longer be applicable based on our facts and circumstances, and the real estate assets and corresponding financing obligation described therein will be derecognized from our consolidated financial statements.

Recently Adopted Accounting Pronouncements

In the first quarter of 2018, we adopted Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers”, ASU 2018-02, “Income Statement-Reporting Comprehensive Income: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” and ASU 2016-16, “Intra-Entity Transfers of Assets Other Than Inventory”.

Each of these is described further below.

Revenue Recognition

In May 2014, the FASB issued ASU 2014-09 which replaces virtually all existing generally accepted accounting principles on revenue recognition and replaces them with a principles-based approach for determining revenue recognition using a new five step model. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also includes new accounting principles related to the deferral and amortization of contract acquisition and fulfillment costs.

We adopted the new revenue recognition standard under the modified retrospective transition method. During the three and nine months ended September 30, 2018, we recorded a cumulative catch-up adjustment that increased our retained earnings by $49 million, net of $17 million of income taxes, and $346 million, net of $117 million of income taxes, respectively. The catch-up adjustment recorded during the three months ended September 30, 2018 resulted from the identification of additional fulfillment costs that should have been considered in our adoption and from correcting certain issues in the accounting system we utilize in calculating revenue under the new revenue recognition standard.

Under ASU 2014-09, we are now deferring incremental contract acquisition and fulfillment costs and are recognizing (or amortizing) such costs over either the initial contract (plus anticipated renewal contracts to which the costs relate) or the average customer life. Deferred acquisition and fulfillment costs are amortized based on the transfer of services on a straight-line basis over the average customer life of 30 months for consumer customers and 12 to 60 months for business customers and are included in cost of services and products and selling, general and administrative expenses in our consolidated statement of operations. A portion of these costs are amortized on a portfolio basis using an average expected contract term of 30 months. The amounts of these deferred costs that are anticipated to be amortized in the next twelve months are included in other current assets on our consolidated balance sheets.

See Note 5—Revenue Recognition for additional information.

Comprehensive Income

ASU 2018-02 provides an option to reclassify stranded tax effects within accumulated other comprehensive income to retained earnings in each period in which the effect of the change in the U.S. federal corporate income tax rate in the Act (or portion thereof) is recorded. If an entity elects to reclassify the income tax effects of the Act, the amount of that reclassification shall include the effect of the change in the U.S. federal corporate income tax rate on the gross deferred tax amounts and related valuation allowances, if any, at the date of enactment of the Act related to items remaining in accumulated other comprehensive income. The effect of the change in the U.S. federal corporate income tax rate on gross valuation allowances that were originally charged to income from continuing operations shall not be included. ASU 2018-02 is effective January 1, 2019, but early adoption is permitted and should be applied either in the period of adoption or retrospectively to each period (or periods) in which the effect of the change in the U.S. federal corporate income tax rate in the Act is recognized. We early adopted and applied ASU 2018-02 in the first quarter of 2018. The adoption of ASU 2018-02 resulted in a $407 million increase to retained earnings and in accumulated other comprehensive loss. See Note 14—Accumulated Other Comprehensive Loss for additional information.

Income Taxes

ASU 2016-16 eliminates the current prohibition on the recognition of the income tax effects on the transfer of assets among our subsidiaries. Prospectively, the income tax effects associated with these asset transfers, except for the transfer of inventory, will be recognized in the period the asset is transferred versus the current deferral and recognition upon either the sale of the asset to a third party or over the remaining useful life of the asset. Our adoption of ASU 2016-16 did not have a material impact to our consolidated financial statements.

Recently Issued Accounting Pronouncements

Retirement Benefits

In August 2018, the FASB issued ASU 2018-14, "Compensation-Retirement Benefits-Defined Benefit Plans-General: Disclosure Framework-Changes to the Disclosure Requirements for Defined Benefit Plans" (“ASU 2018-14“). ASU 2018-14 eliminates requirements for certain disclosures that are not considered cost beneficial, clarifies certain required disclosures and adds additional disclosures under defined benefit pension plans and other postretirement plans. We are required to adopt this guidance beginning January 1, 2021. Early adoption is permitted. The amendments in ASU 2018-14 would need to be applied on a retrospective basis. We are currently evaluating the potential impact of the adoption of this standard on our disclosures.

Goodwill Impairment

In January 2017, the FASB issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment” (“ASU 2017-04”). ASU 2017-04 simplifies the impairment testing for goodwill by changing the measurement for goodwill impairment. Under current rules, we are required to compute the implied fair value of goodwill to measure the impairment amount if the carrying value of a reporting unit exceeds its fair value. Under ASU 2017-04, the goodwill impairment charge will equal the excess of the reporting unit carrying value above its fair value, limited to the amount of goodwill assigned to the reporting unit.

We are required to adopt the provisions of ASU 2017-04 for any goodwill impairment tests, including our required annual test, occurring after January 1, 2020, but have the option to early adopt it for any impairment test that we are required to perform. We have not determined if we will elect to early adopt the provisions of ASU 2017-04. The provisions of ASU 2017-04 would not have affected our last goodwill impairment assessment, but no assurance can be provided that the simplified testing methodology will not affect our goodwill impairment assessment in the future.

Financial Instruments

In June 2016, the FASB issued ASU 2016-13, "Measurement of Credit Losses on Financial Instruments" ("ASU 2016-13"). The primary impact of ASU 2016-13 for us is a change in the model for the recognition of credit losses related to our financial instruments from an incurred loss model, which recognized credit losses only if it was probable that a loss had been incurred, to an expected loss model, which requires our management team to estimate the total credit losses expected on the portfolio of financial instruments. We are currently reviewing the requirements of the standard and evaluating the impact on our consolidated financial statements.

We are required to adopt the provisions of ASU 2016-13 effective January 1, 2020, but could elect to early adopt the provisions as of January 1, 2019. We expect to recognize the impacts of adopting ASU 2016-13 through a cumulative adjustment to retained earnings as of the date of adoption. As of the date of this report, we have not yet determined the date we will adopt ASU 2016-13.

Leases

In February 2016, the FASB issued ASU 2016-02, “Leases” (“ASU 2016-02”). The core principle of ASU 2016-02 will require lessees to present right-of-use assets and lease liabilities on their balance sheets for operating leases, which under GAAP are currently not required to be reflected on their balance sheets.

ASU 2016-02 is effective for annual and interim periods beginning January 1, 2019. Upon adoption of ASU 2016-02, we are required to recognize and measure leases at the beginning of the earliest period presented in our consolidated financial statements using a modified retrospective approach. The modified retrospective transition approach includes a number of optional practical expedients that we may elect to apply.

In January 2018, the FASB issued ASU 2018-01, “Leases: Land Easement Practical Expedient for Transition to ASU 2016-02" ("ASU 2018-01"). ASU 2018-01 permits reporting companies to elect to forego reassessments of land easements that exist or expire before the entity’s adoption of ASU 2016-02 and that were not previously accounted for as leases. We plan to adopt ASU 2018-01 at the same time we adopt ASU 2016-02.

In July 2018, the FASB issued ASU 2018-11, "Leases: Targeted Improvements" ("ASU 2018-11"). ASU 2018-11 provides entities with an additional (and optional) transition method to adopt the new leases standard. Under this new transition method, an entity initially applies the new leases standard at the adoption date and recognizes a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. We have not yet determined whether we will use ASU 2018-11's newly permitted adoption method.

We are in the process of implementing a new lease administration and accounting system. We plan to adopt ASU 2016-02 and ASU 2018-01 effective January 1, 2019. The adoption of ASU 2016-02 will result in our recognition of right of use assets and lease liabilities that we have not previously recorded. Although we believe it is premature as of the date of this report to provide any estimate of the impact of adopting ASU 2016-02, we do expect that it will have a material impact on our consolidated financial statements. Additionally, upon implementing ASU 2016-02, accounting for the failed-sale-leaseback transaction described in Note 3—Sale of Data Centers and Colocation Business will no longer be applicable based on our facts and circumstances, and the real estate assets and corresponding financing obligation described therein will be derecognized from our consolidated financial statements.